Most of room temperature vulcanizable (RTV) silicone rubber compositions are of one-part type and contained in tubes or cartridges as commercially available products so that the silicone rubber may be used simply by extruding the rubber from the container and allowing the rubber to cure with moisture in air. RTV silicone rubber compositions can firmly adhere to various supports and are resistant against heat and weathering. For these and other reasons, RTV silicone rubber compositions have found versatile applications in a wide variety of industrial fields including electric, electronic, building, automobile and business machine industries.
De-alcoholysis type silicone rubber compositions which form one typical class of RTV silicone rubber compositions slowly cure at room temperature. Curing can be accelerated by increasing the amount of a curing catalyst. However, if the amount of curing catalyst added is increased beyond an ordinary level, the composition in uncured state becomes less stable during shelf storage and cured products become less desirable in heat resistance, weather resistance and adhesion.